The present invention relates to a surgical device having a clipping instrument to be inserted through a forceps channel of an endoscope.
Generally, in a clipping instrument for endoscopic surgeries, a clip having a pair of openable/closable arms and a fastening ring loosely fit around proximal portions of the arms is arranged in a distal end portion of a flexible sheath. The clip is configured such that the arms open and close as an operation wire, arranged in parallel with an axial direction of the flexible sheath, is advanced toward the distal end to push the fastening ring and retracted toward a proximal end to pull the fastening ring. The clip can be detached from the operation wire with its arms closed according to the operations to the operation wire. Such a configuration of the clipping instrument is disclosed in Japanese Patent Provisional Publication No. 2006-87537, for example.
FIG. 19 shows a clipping instrument 90 disclosed in the above-referenced publication. A fastening ring 92 fit around a rear portion of openable arms 91 is pushed out of a sleeve 94, which is provided at a distal end of a flexible sheath 93.
The sleeve 94 is formed to have a plurality of slits, which are parallel to an axial direction, so that the fastening ring 92 can resiliently outstretch the sleeve 94 and penetrate therethrough, and the arms 91 can be maintained open.
When the fastening ring 92 passes through the sleeve 94 completely, the resiliently deformed sleeve 94 restores to the original shape, and the fastening ring 92 is restricted from being pulled back into the sleeve 94. Therefore, when an operation wire 96 is pulled toward the proximal end, the arms 91 are pulled in the fastening ring 92 and forcibly closed to clutch onto the body tissue.
When the operation wire 96 is again pushed forward, hooks 97, which are arms of a succeeding clip, are pushed out of the sleeve 94, and the clip 90 is detached from the hooks 97 to be left clutched during the surgery. Thus, an endoscopic clipping operation is conducted.
In the above clipping operation, however, when the fastening ring 92 following the arms 91 is pushed forward to be out of the sleeve 94, considerable force to widen the slits 95 to deform the sleeve 94 is required.
Therefore, when the fastening ring 91 is pushed forward with unintentional excessive force, the clip 90 may be pushed out of the sleeve 94 entirely to be unreturnable in the sleeve 94. In such a case, the arms 91 can no longer be closed.